Anticorrosion agents consisting of the monamides of dimerized fatty acids



2,718,503 ANTICQRRQSION AGENTS GONSISTING OF THE MONAMIDES OF DIMERIZED FATTY ACIDS Albert G. Rocchihi, Springdale; Pat, assi'gnor to Gulf Research &DevelopmmflSompauy,Pittsburgh, Pa., acorporation of Delaware 7 bib-Drawing.v Application. February 20, 1953,

Serial No. 338,125

'21:. Claims. (cr. zen-sits V This invention relates to new anticorrosion agents consisting. ofv the monamides: of. dimerized fatty acids. Among the compoundsembraced by the present. inventiom are the monoamides. ofdimerized dienoicand trienoic fatty acids and primary or secondary amines having an N-substit'uent containing. at least six carbon atoms. The compounds of this invention areparticularly useful for imparting, corrosion inhibiting characteristics and other valuble properties. to various compositions such as, for example,,mineraloiltcompositions.

As wellknown: in. the art, straight or uncompounded mineral oils are often. deficient in: one or more respects for. the particular use to which they are put. For example, a high. resistance to rust or corrosion is important in the case of fuels or lubricantswhich contact metal surfaces intthepresenee of wate1=.- Fuels or lubricants for internal combustion engines'and: for gas-or steam turbinesare examples. of. materials which. may desirably have incorporatedtherein additives or improvement agents whichimpart corrosion inhibiting proper-ties thereto.

Failure to provide sulficient resistance to rust or corro-; sion by a particular. mineral oilmay result inextensive wear or damage to costly, finely-machined, moving parts and/or damage to storage and. transport facilities,- etc. To overcomethisandlother deficiencies of uncompounded mineral oil's, varioustagents known as addition agents, additives, orv improvement agents are commonly incorporated inzthe particular mineral oiLto be used Anobject-of thisinventionis to'provide new chemical" compoundsv which remedy the above-mentioned deficien cies and which have-valuable industrial uses. A- further objcctis? to provide aprofcessfor the: preparation of: said new chemicalcompoundsi. An: additional: object is to" provide new mineral oil compositions containing. the

above-mentioned: chemical compounds: and having: improved rust. and corrosion inhibiting characteristics.

These androther object's are aehievedby the present'inventionr whiclrgincludes monoamides of primary or sec: ondary amines having an N-substituent containing at least 6 carbon atoms and dimers of unsaturated fatty acids containing from 6 to 22 carbon atoms and having from 2 to 3' ethylenic link-ages per molecule. These monoamidesmaybe in the form of the acid amide or alternatively, may be-in the form of asubstantially neutral salt of theacida'mide. The invention also includes processesfor preparingthe described monoamides as well as mineral oil compositions containing the same.

In general, the compounds of this invention may be defined by the following generic formula:

2 where is the acyl residue of adimerized polyolefinic fatty acid,

where n is an integer of from 10 to 42, where xis an even integer of from 6 to 10; whereRl is aradical containing at least 6 carbon atoms selected from the group consisting of aliphatic, aromatic, aliphatic-aromatic and aromatic-aliphatic radicals, where R is an organic radical, preferably of the same kind as R1, or hydrogen,

' Where Z is hydrogen, or a salt'-forming metal and y is an integer equal to the valence of Z. The invention also includes preparation of compounds of the type denoted above and mineral oil compositions containing'the' same;

The dimerized acids referred to above are' dimers, i. e., bimolecular addition products, of conjugated or nonconjugatedpolyolefinic (dienoic to trienoic), fatty a'cidshaving from 6:to 22carbon atoms'before dime'rization. Such dimeri'zedfatty acids may be prepared by known methods. Briefly, one method of preparation of saiddim'erized' acidsinvolveslsubjec'ting the monomer of a polyolefinicfatty acid of 'the type described to heat treatment at about- 300 C. to about 360 C. for from aboutthree to about eighthou'rs' under about 85 to about 400' pounds steampressure. The dimer acid is recovered from the reaction mixture by distillation A- second method for preparing the dimerized acids involves heating the methyl ester of the polyolefinic fatty acid-at about 300 C. for several hours in an inert atmosphere, e. g'., carbon dioxide. The resulting dimerized ester is then separated by distillation and saponified. The dimerized acid is then prepared from the s'aponifiedprodnot by' acidification with a mineral acid, such as hydrochloric acid.

In general, dimerized acids suitable for purposes ofthis invention are those prepared from polyolefinic monocarboxylic acids having the generic formula:

. where n is an integer of from 5 to 21 and x' is 3 or 5.

As will be evident, such monomeric acids contain from- 6-to 22 carbon atoms and may contain 2 or 3' ethylenic linkages as the ratio of carbon to hydrogen increases (i; e., as xincreasesfrom 3 to 5); Dimerized acids corresponding to the additionproducts of the foregoing acids" therefore may be defined by the generic formula:

where n is an integer of from 10 to 42, and where x is an even integer from 6 to 1-0. These dimeric-acidsare therefore dibasic acids having from 12 to 44 carbon Patented Sept. 20, 1955 3 atoms, and especially those having conjugated olefinic linkage are distinctly preferred.

It is not necessary that both of the unsaturated fatty acid molecules of the bimolecular addition product be identical. Dimers of mixed composition, such as those obtained by dimerizing mixtures of dienoic, trienoic, or dienoic and trienoic acids obtained from naturally occurring drying oils are quite satisfactory.

A wide variety of primary and secondary amines which do not adversely affect the oil-solubility of the monoamide can be used in the preparation of the agents of this invention. Primary and secondary amines having a substituent containing at least 6 carbon atoms definitely assist the oil-solubility of the additives. In general, amines suitable for the purposes of this invention are primary or secondary monoamines or mixtures thereof having the generic formula:

1 H-N-Ra where R1 and R2 are as defined above. Particularly suitable are amines containing aliphatic N-substituents, including saturated, unsaturated, acyclic, cyclic and poly cyclic substituents containing more than 6 carbon atoms.

Illustrative of suitable primary amines are the alkyl amines, such as hexyl, octyl, decyl, dodecyl, tetradecyl, octadecyl, eicosyl and hexacosyl amines. Although amines having substituent chains containing more than 26 carbon atoms may be used, the shorter chain amines are preferred for reasons of commercial availability. Primary alkenyl amines such as heptenyl, nonenyl, undecenyl, pentadecenyl and pentacosenyl are also satisfactory. Examples of suitable primary cycloaliphatic amines are cyclohexyl and substituted cyclohexyl amines. Primary, polycyclic or polynuclear aliphatic amines, such as rosin amines, or the amine of abietic acid are also satisfactory. Monocyclic aromatic amines, such as aniline, as well as polycyclic or polynuclear aromatic amines such as diphenyl amine and alphaand betanaphthylamines also have utility in the present invention. Benzylamine and betaphenylethylamine are illustrative of suitable aromaticaliphatic amines, just as toluidine and xylidine are exemplary of suitable aliphatic-aromatic amines.

Secondary amines corresponding to all of these classes of amines are also utilized to advantage and include not only secondary amines having identical substituents such as dioctylamine, dioctenylamine, dicyclohexylamine, N,N- diphenylamine, dibenzylamine, and N,N-ditolylamine, but also secondary amines having different substituents from the same class, such as N,N-octylhexadecylamine and N,N-phenylalphanaphthylamine, as well as secondary amines whose substituents are selected from different classes such as N,N-octylphenylamine, monomethyl aniline, N,N-phenylcyclohexylamine and the like.

Among the numerous classes of amines suitable for the purposes of this invention, the commercial mixtures of high molecular weight amines derived according to conventional methods from naturally occurring substances, such as cocoanut oil, palm oil, animal fats, rosin and the like, are distinctly preferred.

The various amines described above are representative of the class of amines having from one to two N-stubstituents, at least one of which contains at least six carbon atoms.

The reaction by which the compounds of this invention are prepared involves partial amidation of a dicarboxylic acid with a primary or secondary amine. This reaction is entirely conventional and is carried out according to known procedures and according to known conditions. Therefore, the reaction need only be described briefly.

In this connection, the dimerized acid and amine are admixed in equimolecular proportions. The reactants may be reacted directly with each other or in the form of a solution or dispersion containing the reactants. It is particularly preferred to dissolve the reactants in a mineral oil solvent and to carry out the reaction with the reactants in solution, since localized heating is avoided. Moreover, the product resulting from this procedure is in the form of a mineral oil concentrate containing a substantial proportion, e. g., from one per cent up to the limit of solubility, of the additive. The resulting concentrate may then be blended with the desired vehicle in the desired proportions. Solution of the additive in the ultimate carrier therefore is often greatly facilitated by this expedient.

While the amidation reaction discussed above normally takes place to some degree even at relatively low temperatures, it is desirable to employ heat of a degree at least equal to the boiling point of water, i. e., 212 F., in order to eliminate the water of reaction, and in order to force the reaction to completion. It is preferred that temperatures of not substantially in excess of 350 F. be employed, since decomposition of the product may result. A preferred procedure involves terminating the reaction when the temperature of the reaction mixture reaches a degree not substantially above about 250 F., and allowing the product to cool.

While heat is important in effecting the reaction for the reasons indicated above, it is to-be noted that no extraneous source of heat may be necessary when primary amines are reacted. In such instances the heat of reaction is often sufficient of itself to provide a temperature of 250 F. or higher.

Normally, the reaction is complete after about 15 to 30 minutes, or after substantially all of the Water of reaction has been removed.

The products of the above-described reaction are the acid amides of dimerized polyolefinic fatty acids. The reaction products normally vary in appearance from waxy solids or semi-solids to viscous, tacky liquids. The color of the products normally varies from straw-colored to dark.

The neutral salts of the acid amides may be conveniently prepared by reacting the acid amide with an alkali metal alcoholate. The resulting alkali metal salt may be used as such, or alternatively other metal salts may be prepared by metathesis of the alkali metal salt of the acid amide with a salt of the desired metal. This procedure is described in greater detail in U. S. Patent 2,458,425. Illustrative of metals which provide desirable metallic salts according to this invention arez-sodium, lithium, potassium, barium, calcium, magnesium,-

strontium, lead, copper, iron, nickel, mercury, zinc, bismuth, aluminum, chromium, tin, manganese, silver and cadmium.

Examples I to V, following, are representative of the mode of preparation of the various compounds of this invention. It is understood that the examples are by way of illustration only and are not intended as limiting.

EXAMPLE I The dimeric acid employed in this example was Emerys M-461-R dimer acid, manufactured by Emery Industries, Inc., Cincinnati, Ohio. M-461-R dimer acid is a commercial form of a dimeric polymer consisting essentially of dilinoleic acid (the dimer of 9,ll-octa- The commercial dimer acid hadthe following pliysical properties:

Physical. state Straw-colored, viscous liquid Molecular weight (approx.) 560 Neutral equivalent 298- 310 Iodine value 80-95 Dimer content (approx).. a a. a ..percent 85 Trimenandlhigher(approx.).. a do- 12 Monomer (approx.); do' 3 The compound of this example was prepared by mixing 56 parts by weight of the M-46'1-R dimer acid with 31.3 parts by weight of Armeen S. The latter is a commercial mixture of long-chain, primary amines having a molecular weight of about 313. The mixture is composed primarily of octadecadienyl amine and octadecenyl amine and is manufactured by Armour & Corn-- pany of Chicago, Ill. 7

The reaction mixture reached a temperature of above. 250 F. without application of extraneous heat. After the reaction was complete, i. e., after about. minutes, the product was allowed to cool. The product contained predominantly a mixture of the acid amidesof dilinoleic acid and 18-carbon, primary, alkenyl amines. This product was a waxy solid of amber color.

EXAMPLE II To 56 parts by weight of Emerys M-461-R dimer acid were added 31.0 parts by weight of Armeen T," a com-- mercial mixture of octadecenyl amine, octadccyl amine and hexadecylamine (manufactured by Armour & Com

EXAMPLE HI Emerys M-46l-R' dimer acid in the proportion of 56 parts by weight was added to and stirred with ten parts by weight of cycl'ohexylamine. The reaction" mixture reached a temperature of above 250 F. without application of'extraneous heat. After the'reaction was complete, ii e., after'about 20 minutes, the product was allowed to' cooli The product obtained was a: mixture of the acid amides ofcyclohexylamine and dilinoleic acid. In appearancethe product was a viscous, waxy, tacky, semisolid.

EXAMPLE IV Dicycloliexylamine in. the proportion. of 18 parts by weight was. added. to 56 parts by weight of Emerys- M-461-R dimer acid with stirring. Thisreaction required heating. After the reaction was complete, i. e., after a temperature of 250 F. had been reached, the mixture was allowed to cool. The product of this reaction was a dark, viscous, tacky liquid and contained predominantly a mixture of the acid amides of dilinoleic. acid and dicy clohexylamine.

EXAMPLEV Fifty-six parts by weight of Emerys M46lR dimer acid' were stirred with 32 parts by weight of rosin amine D, manufacturedby Hercules Powder Company, ofWilmington, Delaware, and containing essentially the primary amine of abietic acid, and having a molecular. weight ofv about. 320. The. reaction. proceeded. vigorously in-.an. exothermic fashion. After the reactionwas. complete, i. e., after the temperature had reached about 250 F., the mixture was allowed to cool. An amber, viscous 6 liquid comprising predominantly a mixture of. the. acid amides of the amine of. abietic' acid and dilinoleic acid was obtained.

Acid amides of other dimerized polyolefinic fatty acids and other disclosed amines can be obtained in substantially identical fashion. The neutral salts of these acid amides can be obtained in. the manner disclosed above.

The reaction products resulting from the above-described procedures, either alone or in the form of a. solution concentrate, may be incorporated in the desired vehicle. Where the vehicle is a mineral lubricating oil, e. g., a turbine oil, the reaction products are employed in a minor proportion, sufiicient to confer rust and corrosion inhibiting properties upon the latter. Normally, from about 0.02 per cent to about 1.0 per cent of the additive by weight of the composition is" sufiicient for this purpose, although greater proportions may be employed, if desired. Examples of various mineral oils which are benefited by the compounds of this invention are gasoline, kerosene, diesel fuel, furnace oil, motor oils, lubricating-greases,and tur bine: oils. The invention further includesmineral oil compositions; where the solvent constituent is not employed as a fuel or' lubricant, but merely as a solvent vehicle.. Exemplary of this type of composition are light naphtha and like oil solvents containing the novel compounds of this invention.

The following. example will serve to illustrate. moreclearly the preparation of the novel mineral oil compositions included in. this invention as Well as the desirable results obtained bytheir use.

EXAMPLE VI To each of five samples of a highly refined, highly paraflinic, turbine: oilhaving a gravity of between: 3015" to: 32.54 API and aviscosity of about 150 Saybolt Universal: seconds. at 1.00" F; was added 0.25 per cent by weight of one of the products prepared in the foregoing Examples I to V. sixth sample of the untreated turbine oil was utilized as a control or blank. Each of the six' samples mentioned was then tested according to the pro visions of ASTM corrosion test D665.'47 T, procedure A. Following this'test, three of the oil samples were furthersubjected to the-Film Tenacity test.

ASTM corrosion tent-This test is that specified. in the ASTM: Standards of. Petroleum Products. and Lu-' bricants, November 1948, and is designated as.ASTM=D- 665-47 T. In brief, procedure A of this test involves. placing a 300 ml; sampleof the oil in a.400'ml. beaker which is, in turn, immersed in a'constant temperature bath maintained: at a temperature of F. The beaker is. fittedwith-a cover providedwith openings for a stainless. steel, motor-driven stirrer and for insertion of astandard steeltest. bar having a diameter of 0.50 inch and a: length of approximately 5.5 inches which has been carefully cleaned and polished according to a prescribed procedure just priorsto the test. The stirrer is started and when the oil sample in the beaker reaches a temperature of 140 F., the test bar" is lowered through the proper opening and is suspended from the beaker. cover. After thirtyminutes, 50 ml. of the oil are removed and replaced with 30 ml. of distilled water. Stirring is then continued for 48 hours with the temperaturev maintained. at 140 F. At the end of this period the steel bar is removed and examined for rust spots.

Film tenacity test.-This test is designed to evaluatecorrosion resistance of the film of.the oil compositionas. applied to steel surfaces. It. is carried out immediately' after the ASTM corrosion test. described above. If the steel test bar used in the ASTM test shows noevidenceof. rusting,, it.is. suspended in.the.mouth of. a. 300ml. flaskand is allowed to drain. The beaker containing the-oil.

sampleis. removedfrorn the constant temperature bath and isreplaced with a clean beaker containing 300 ml.- distilled water. With the stirrer operating, the tempera-- ture of the water in the beaker is allowed to reach 140 F.

When the test bar has drained for a period of thirty minutes it is inserted in the beaker as above. Stirring is continued for 24 hours, after which the test bar is removed and examined for rust spots.

It will be seen that this test is quite drastic, since throughout its operation the steel test bar is protected from the rust only by a thin residual film of the oil being tested. It not only evaluates the protection against rusting provided by the composition, but also indicates the tenacity with which a film of the composition adheres to the metal surface.

The results of the foregoing tests are presented in Table A below:

What I claim is:

1. A monoamide of an amide having from 1 to 2 hydrocarbon N-substituents at least one of which contains at least 6 carbon atoms and a dimer of an unsaturated fatty acid containing from 6 to 22 carbon atoms and hav ing from 2 to 3 ethylenic linkages per molecule.

2. The compound of claim 1 where the unsaturated latty acid contains 18 carbon atoms.

3. A monoamideof a primary aliphatic amine containing from 16 to 18 carbon atoms and a dimer of linoleic acid.

4. A monoamide of cyclohexylamine and a dimer of linoleic acid.

Table A Percent AB'IM Corro- Filrn Te- Sam 19 by Wt. slon Test f Base Stock Additive Addb D6654, T 11 1 tlve (A) 1 Turbine Oil... Acid Amides of Dimerized 0.05 No Rust NoBust.

Linoleic Acid and Armeen S (Example I). 2 .do Acid Amides of Dimerized 0.05 do Do.

Linoleic Acid and 'Armeen T (Example II). 3 do Acid Amides of Dimerized 0.05 do Linoleic Acid and cyclohexylamine (Example III). 4 ..do Acid Amides of Dimerized 0.05 do Linoleic Acid and Bicyclehexylamine (Example IV). 5 do Acid Amides of Dimerized 0.05 do No Rust.

Linoleic Acid and Rosin Amine "D" (Example V). 6 .do None 0 Heavy Rust.

Not tested.

Snmlar improvements are obtainable by the use of 5. A monoamide of dicyclohexylarnine and a dimer of monoamides prepared from other of the disclosed primary and secondary amines and from other of the disclosed dimer acids.

The results reported in Table A indicate that extremely small proportions of the compounds of this invention confer a high resistance to corrosion and an improved film tenacity on the oil composition.

The described novel compounds also can be employed in conjunction with gasoline, furnace oil, diesel fuel, slushing oil, motor oils and other oils. The use of the additives in lubricants is considered particularly advantageous, since the additives are considered to enhance the lubricating qualities of the carrier. As has been indicated, the described monoamides can be incorporated in mineral oil products, such as light naphtha, which are employed neither as a fuel nor as a lubricant. In such instances the compositions find use in the coating art, whereby a metallic article subject to rust or corrosion is brushed, dipped or sprayed with the composition comprising the solvent vehicle and the additive. Subsequent evaporation of the solvent leaves the adherent, corrosion resistant coating of the additive on the article. The compounds of this invention also find utility as corrosion inhibiting additives for various paints, varnishes, automobile undercoatings and the like. In the use of the agents of this invention in various coating compositions, it may be desirable to employ the compounds in substantially greater concentrations than are normally utilized in fuels and lubricants.

It is to be understood that the improved mineral oil compositions of this invention can be additionally improved by incorporation therein of other known additives in order to confer other desirable porperties such as increased resistance to oxidation, increased stability, etc., thereon. Thus, there can be added viscosity index improvers, thickeners, bearing corrosion inhibitors, antioxidants, dyes, etc.

Numerous modifications of the invention within the scope of the foregoing description and the appended claims will suggest themselves to those skilled in the art.

linoleic acid.

6. A monoamide of a primary rosin amine and a dimer. of linoleic acid.

7. A method of preparing a monoamide of a dimerized unsaturated fatty acid comprising reacting an amine having from 1 to 2 hydrocarbon N-substituents at least one of which contains at least 6 carbon atoms with substantially equimolecular proportions of a dimer of an unsaturated fatty acid containing from 6 to 22 carbon atoms and having from 2 to 3 ethylenic linkages per molecule.

8. The method of claim 7 where the dimer and the amine are reacted in a mineral oil solution.

9. A corrosion inhibiting concentrate for addition to mineral oil compositions comprising a mineral oil solvent and a substantial proportion of a monoamide of an amine having from 1 to 2 hydrocarbon N-substituents at least one of which contains at least 6 carbon atoms and a dimer of an unsaturated fatty acid having from 6 to 22 carbon atoms and containing from 2 to 3 ethylenic linkages per molecule.

10. A mineral oil composition comprising a major amount of a mineral oil and a minor amount, sufficient to impart corrosion inhibiting properties to the composition, of a monoamide of an amine having from 1 to 2 hydrocarbon N-substituents at least one of which contains at least 6 carbon atoms and a dimer of an unsaturated fatty acid having from 6 to 22 carbon atoms and containing from 2 to 3 ethylenic linkages per molecule.

11. The composition of claim 10 where the unsaturated fatty acid contains 18 carbon atoms.

12. The composition of claim 10 where the mineral oil is a lubricating oil.

13. The composition of claim 10 where the mineral oil is a turbine oil.

14. A mineral oil composition comprising a major amount of a turbine oil and a minor amount, sufficient to impart corrosion inhibiting properties to the compo-' sition of a monoamide of a primary aliphatic amine containing from 16 to 18 carbon atoms and a dimer of linoleic acid.

15. The composition of claim 14 where the monoamide is present in the proportion from about 0.02% to about 1.0% by weight of the composition.

16. A mineral oil composition comprising a major amount of a turbine oil and a minor amount, suflicient to impart corrosion inhibiting properties to the composition, of a monoamide of cyclohexylamine and a dimer- 20. A mineral oil composition comprising a mafor amount of a turbine oil and a minor amount, sufiicient to impart corrosion inhibiting properties to the composition, of a monoamide of a primary rosin amine and a dimer of linoleic acid.

21. The composition of claim 20 where the monoamide is present in the proportion from about 0.02% to about 1.0% by weight of the composition.

References Cited in the file of this patent UNITED STATES PATENTS 2,190,770 Carothers Feb. 20, 1940 2,216,312 DeGroote et a1 Oct. 1, 1940 2,330,524 Shields Sept. 28, 1943 2,484,010 Bried Oct. 11, 1949 2,584,784 Biswell Feb. 5, 1952 2,631,979 McDermott Mar. 17, 1953 

10. A MINERAL OIL COMPOSITION COMPRISING A MAJOR AMOUNT OF A MINERAL OIL AND A MINOR AMOUNT, SUFFICIENT TO IMPART CORROSION INHIBITING PROPERTIES TO THE COMPOSITION, OF A MONOAMIDE OF AN AMINE HAVING FROM 1 TO 2 HYDROCARBON N-SUBSTITUENTS AT LEAST ONE OF WHICH CONTAINS AT LEAST 6 CARBON ATOMS AND A DIMER OF AN UNSATURATED FATTY ACID HAVING FROM 6 TO 22 CARBON ATOMS AND CONTAINING FROM 2 TO 3 ETHYLENIC LINKAGES PER MOLECULE. 